The present invention relates to an improved coupler for ductile or deformable tubing.
There is a large variety of fittings or couplers available for connecting or joining ductile or deformable tubes or pipes together. Tubing of this type includes various composition tubing such as, for example, tubes made of various types of plastic, nylon, rubber, or other soft and malleable materials, such as wood, soft metals, etc.
Such couplers are used to join tubes in a number of different ways. For example, some are linear to join a pair of tubes, end-to-end. Others form elbow, T, and cross configurations. Various other multiple-port configurations are also
One of the most common types of coupler used to join ductile tubing of this type is sometimes referred to as the compression-nut type. U.S. Pat. No. 2,473,118 and No. 3,007,721 are examples of this type of coupler. Typically, this type of connector includes a body having a receiving bore or port into which a tube to be coupled is inserted. The body is threaded along its exterior surface. A ferrule fits over the end of the tube to be coupled. A compression nut encircles the end of the ferrule and screws onto the exterior of the body. At the same time, it engages the ferrule and as it is screwed onto the body it forces the ferrule axially along the tube and is radially contracted so that it "bites" into the tube. This locks the tube within the body and creates a fluid seal.
While functionally this type of connector is satisfactory, it has several significant disadvantages. For each connection, three individual parts are required. If, for example, the nut is lost or damaged, unless other parts are available, it is not possible to make the coupling. Also, tools are required to tighten the compression nut and care must be taken to tighten the nut to insure a good seal but not so tight as to rupture the tube.
Also, with many couplers of this type, in the process of tightening the compression nut, the ferrule is damaged or deformed and is not reusable.
There are threadless connectors in the prior art but these also require a multiplicity of parts. For example, in one such patent, U.S. Pat. No. 2,831,711, a separate sealing ring is provided in addition to a locking ring.